System.Collections 命名空间下几个常用的类

1. 可以存储重复的 Key ，相同Key的值以","隔开

            // Creates and initializes a new NameValueCollection.
            NameValueCollection myCol = new NameValueCollection();
            myCol.Add("red", "rojo");
            myCol.Add("green", "verde");
            myCol.Add("blue", "azul");
            myCol.Add("red", "rouge");

            // Displays the values in the NameValueCollection in two different ways.
            Console.WriteLine("Displays the elements using the AllKeys property and the Item (indexer) property:");
            PrintKeysAndValues(myCol);
            Console.WriteLine("Displays the elements using GetKey and Get:");
            PrintKeysAndValues2(myCol);

            // Gets a value either by index or by key.
            Console.WriteLine("Index 1 contains the value {0}.", myCol[1]);
            Console.WriteLine("Key \"red\" has the value {0}.", myCol["red"]);
            Console.WriteLine();

            // Copies the values to a string array and displays the string array.
            String[] myStrArr = new String[myCol.Count];
            myCol.CopyTo(myStrArr, 0);
            Console.WriteLine("The string array contains:");
            foreach (String s in myStrArr)
                Console.WriteLine("   {0}", s);
            Console.WriteLine();

            // Searches for a key and deletes it.
            myCol.Remove("green");
            Console.WriteLine("The collection contains the following elements after removing \"green\":");
            PrintKeysAndValues(myCol);

            // Clears the entire collection.
            myCol.Clear();
            Console.WriteLine("The collection contains the following elements after it is cleared:");
            PrintKeysAndValues(myCol);

        public static void PrintKeysAndValues(NameValueCollection myCol)
        {
            //IEnumerator myEnumerator = myCol.GetEnumerator();
            Console.WriteLine("   KEY        VALUE");
            foreach (String s in myCol.AllKeys)
                Console.WriteLine("   {0,-10} {1}", s, myCol[s]);
            Console.WriteLine();
        }

        public static void PrintKeysAndValues2(NameValueCollection myCol)
        {
            Console.WriteLine("   [INDEX] KEY        VALUE");
            for (int i = 0; i < myCol.Count; i++)
                Console.WriteLine("   [{0}]     {1,-10} {2}", i, myCol.GetKey(i), myCol.Get(i));
            Console.WriteLine();
        }

运行结果：

2. 按照 Key 的顺序存储（英文是a在前，z在后）

            SortedDictionary<string, List<string>> sortedDicItems = new SortedDictionary<string, List<string>>();
            sortedDicItems.Add("bac", null);
            sortedDicItems.Add("abc", new List<string>() { "Bruce", "Jack", "Rose" });
            sortedDicItems.Add("001", null);
            foreach (KeyValuePair<string, List<string>> item in sortedDicItems)
            {
                Console.WriteLine(item.Key);
            }

运行结果：

谢谢浏览！